THE ALBUMINOIDS O F MAIZE.
-
By
n ~GEORGE . ARCHBOLD.
Under this heading it was my first intention to have readan elaborate paper on the subject; but time and circumstances a t my command are such that this must be considered only preliminary; inasmuch as it involves a very important feature in the manufacture of starch from maize. According to published analyses of average corn which is used in the 22 principal factories engaged in the manufacture of starch, the total albuminoids consist of ten and one-half per cent. of the maize. This includes what is commonly known as gluten, or nitrogen-yielding products. I n the usual methods of making corn starch, it has been found advisable to macerate the corn under water at varying temperature@,with a view of softening the corn, and a t the same time putting it in such a condition that it can be ground into a pulpy mass, and that all except the cellulose can be disintegrated from the mass. I t will be obvious that a certain amount of thealbuminoids will escape tt sieve or any mechanical method of separation. It will also be understood that the time required, varying from three days to a week, for the softeuing of the grain in question requires a temperature sufficient to resohe anything of an albuminoid nature itself into further compounds of a very complex nature. I n view of these facts, I have tried to find by direct investigation of the pure corn whether or not these albuminoids have undergone a decompositioii that would entitle me to form a true hypothesis of the solution i n question. With this pnrpose, I have taken corn recently grouiid and reduced it to an impalpable powder, and have placed it in a sealed box and forced water into it, until the extract thtit came from it showed nothing ~ i p o nevaporation in a platinum dish except the salts existing in the water and a portion of the soluble
31.1
T H E ALRGMIKOIDS OF MAIZE.
salts that existed in the maize. This being done all at a temperature not exceeding 70- F., I have taken the total aqueous extract, which was neutral to litmus paper, and added alkali to it, which precipitated a flocculent mass, giving 16.7$ of nitrogen. When this was collected and dried in the air, i t gave many of the properties of diastase. The magma that was in the box above referred to, Ly wliicli 1 made the extraction under pressure with water at 70' F., mas further ground so that all except the cellulose mould go through an SO mesh sieve, by repeated washings a t 70" F.; or until the magma contained nothing but pure cellulose, thereby hacing all that passed through the sieve in a state of suspension, namely the starch and the albuminoids contained in t h e corn treated t!mt were soluhle in water. I now added by degrees to the total that had gone through the sieve a solution of caustic soda of a gravity of S' until it gave it coloration of iz greenish yellow color. This was done in a beaker, and the result wits tliat a flocculent precipitate of a brownish green color fell to the bottom, and the starch was lieid in suspension in t!ie upper strata of the liquid. Tlnless sufficient alkali is added the starch will fall to the bottom. I drew off by the usual methods of siphoning and by a repeated washingwith distilled water and obtained the starch practically pure. But this water when mixed together from the several washings of starch, contained an albuminoid, precipitated on neutralizing with hydrochloric acid as a light brown substance which, when dried at 212' F., or until i t ceased to lose weight, gave 136 of nitrogen. The starch was practically pure. The substance underneath the strata of suspended starch which I have mentioned above, was of a greenish color, and contained only a small percentage of nitrogen. It appeared to be in part an insoluble soap, and contained most of the oils contained in the corn. Supposing that I had taken corn or maize from the steeps, and separated the starch by the means herein set forth, I would obtain different results and be able to gain nearly the same amount of nitrogen but would also separate substances of albuminoid nature, that I will submit to this Society later on. Kow, under these circumstances, when commercial maize in the dried state, such as I submit herewith, is taken, and when the
T H E ALBUXIXOIDS OF MAIZE.
315
cxperiments are carried ont as I have stated, it will be found tliat only two definite albuminoid substances are obtained, one of which is thrown down by alkalies as a greenish precipitate, and the otlieisoluble in alkalies, which precipitate is of a greenish color (except ammonia, which yields a white precipitate) and precipitated by -cids. By the most careful methods iiscd in varioiis factories, the whole of the albuminoids tliat are soluble in alkali are never eiitirely washed out as will be sl~owni n the various colorations. in the starches found in the American market, ,which show the variation in composition.
1
2 3 4 5 B
96.250 None None 0.098 95.821 None None 0.100
None 0.420 0.200 0.400 0.400 0.400 0.190 0.200 0.099 0.700 0.249 0.600 0.201 0.800 0.100 0.400 0.190 0.200 0.050 0.400 _ _ - - - 1.600 0.423 1.000 0.260 0.800 0.198 0.620 0 280 0.800 0.110 1.120 0.480 0.600 0.381 0.600 0.410 1.400 0.912 1.549 0.150 1.100 0.519 1.000 0.301 1.000 0.5551 1.000 0.325 1.100 0 389 1.479 0.481 0.800 0 210 1.000 0.009 0.800 0.851 0.400 0.816 0.800 0.800 1,400 0.750 I .*510
88.OOo 89.250 88.280 88.000 7 88.010 e 87.901 9 88.210 10 87.561 11 87.200
12 13 14 15 16 17 18 19 20 21
22 83 22 25
26 27 28 29
30 31 32 33 32 35
96".2+ 95".8+ 87".9+ 89". 87".9+ 87".9+ 87'.5+ 87".8+ 87".9+ 87'.3+ 87". 87". 87'. s7;. 86 .9+ 86".5+
0.100 0.110 0.381 0.110 0.201 0.750 0.220 0.439 0.310 87.000 0.150 87.000 0.250 87.000 0.327 86.920 0.750 86.725 0.211 86.500 0.721 86.520 0.750 87.260 0.421 87.260 0.300 87.520 0.330 87.253 1.010 8~.9on 0.211 86.821 0.411 86.250 0.221 Y6.225 0.120 B6.225 1.100 37.110 0.501 97.234 1.100 37.210 0.110 37.250 0.110 37.110 0.230 36.521 0.933 35.430 1.120 32.250 1.120
+
+ + + +
86".5+ 86'.4+
87". 87". 87".
+
*+
86".9+ 85..5+ 86'. 86". 86 . H.i'.5+ 87=, 86-.8+ 87O.
+ +
+
-+-
87".
+
-+
83".2+ 85".9+ 84.. 8 2 O . -4-
+
I
-
1
0.090
0.100 1 0.223 0.821 0.221 0.091 0.500 I 0 380 0.421 0 200 0.090 0.200 1.311 0. a22
11
0.621
0.420 0.590 0.801 0.360 0 321 0.831 1251 0.621 0.721 0 681 0.725 0 791 1.010 0 541 0.762 I 0 521 0.138
0.330 0.922 0.821
i
1
___1
MISE D S'I' ARC HE S. I
85.2301 0.220 t15.231 0.530 79,9251 0.811 80.250 0.521 79.210 0.310 80.9211 1.121
i
0.321 I.003 0.249 0.389 21.350 0.320 0.331 1.959 0.110 0.430 2.275 0.225 0.421 7.Ooo 0.120 0.726 5.450 0.321
0.110 ...-
11.848 10,252
0.991 1.210
1
1
PIAL CORK STARCII. IITIEY.
-
Cnlcium
1.
-
3ulphnte
!M Y 1 1 1 5
2
9 2 0 0 7 D 1
a a R
8 B 1
0.228
7 I 1
6 1
3 3
3
1 1 i
1 I 1 -
-~
REMARKS.
3cdium Ihloride.
Superior quality of starch, being .four to five times purer than average commercial starch. A fair sample of commercial starch. An average sample commercial btnrch. An average commercial starch. An average commercial starch. A fair commercial starch. An im ure commercial starch. Unfit POr culinary use. A poor sample of commercial starch. A fair sample of commercial starch. .4n average sample of Yice starch. Excess of caustic alkali. An ordinary commercial starch. A fair commercial sample. A fair commercial sample. Too impure for culinary use. Too high in mineral matter for food. Impure commercial sample-excess alkali. Impure commercial sample-excess alkali. h very impure starch, unfit for food. Below standard of commercial purity. A rery impure starch, unfit for human food. A very ordinary sample of starch. 0.100 Too high in mineral impurities for culinary use. An impure commercial starch. Too high in mineral impurities for food. Too high in mineral impurities and alkali for food. Imperfectly separated and impure. A fair commercial sample with excess of alkali. A very impure rice starch with excess of alkali. A poor starch, strength killed by use of free alkali. Very impure and imperfectly prepared. Very impure and unfit for culinary purposes. 0.088 Contains an abnormal $ alkali-unfit for food ____
